These are not designed to be portable, though demountable/removable ones certainly exist nowadays. At both of my houses in Sydney when growing up, they were set in the ground in concrete.
So, I am not surprised you'd never see these anywhere outside of a generally sunny climate. Space is also a factor - the average yard size in Australia is far larger than that of the UK, though it is shrinking in the major cities.
The handle certainly helps to prevent head injuries when mowing the lawn around them. I've hurt myself a few times after forgetting to wind ours back up.
So, I am not surprised you'd never see these anywhere outside of a generally sunny climate. Space is also a factor - the average yard size in Australia is far larger than that of the UK, though it is shrinking in the major cities.
The handle certainly helps to prevent head injuries when mowing the lawn around them. I've hurt myself a few times after forgetting to wind ours back up.